#include <iostream>
#include <string>

using namespace std;


namespace Func
{
    int add(int val_1 ,int val_2);
};

using namespace Func;

int Func::add(int val_1 , int val_2)
{
    return val_1 + val_2;
}

namespace student_system
{
    namespace log_in
    {
        string name;
        string password;
        int id;
    };

    namespace student
    {
        string name;
        int id;
    };
}

using namespace student_system;

int main(int argc, char const *argv[])
{
    student_system::student::name = "aa";

    student::name = "zz";

    cout <<"func add =  "<<Func::add(90,80) << endl;

    cout <<"student name =  "<< student::name << endl;

    cout <<"student name =  "<< student_system::student::name << endl;
    return 0;
}
